Method of manufacturing plate-shaped bonded body, bonding device, and plate-shaped bonded body

ABSTRACT

A method for quickly applying and spreading adhesive between substrates without leaving air bubbles. The method includes holding two substrates apart from each other with adhesive sides facing, a second substrate being positioned above a first substrate. The second substrate is suspended in a manner so as to cause a portion to warp towards the first substrate. After a liquid filler is applied between the two substrates, rollers are lowered onto the second substrate and moved so as to disperse the liquid filler between the first and second substrates. In accordance with the rolling of the rollers, end portions of the second substrate are lowered towards the first substrate.

This is a divisional application of U.S. patent application Ser. No.13/824,828 filed on Mar. 18, 2013, which in turn is a National PhaseApplication of International Application No. PCT/JP2011/079371 filed onDec. 19, 2011, which in turn claims priority to Japanese Application No.2010-285690 filed on Dec. 22, 2010. The prior applications areincorporated herein by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to a method of manufacturing a plate-shapedbonded body obtained by bonding plate-shaped bodies, a bonding devicefor a plate-shaped body and a plate-shaped bonded body manufactured byusing the device, and the invention can be suitably used particularlyfor a plate-shaped bonded body that is manufactured by filling a fillerbetween large-sized plate-shaped bodies.

The present application asserts priority rights based on JP PatentApplication 2010-285690 filed in Japan on Dec. 22, 2010. The totalcontents of disclosure of the Patent Application of the senior filingdate are to be incorporated by reference into the present Application.

BACKGROUND OF THE INVENTION

Conventionally, liquid crystal display panels have been increasingemployed as image display devices for use in televisions, personalcomputers, personal digital assistants or cellular phones. Among these,a liquid crystal display device obtained by bonding a cover glass and aliquid crystal display panel using a transparent resin having arefractive index equivalent to that of the cover glass is advantageousin view of picture qualities such as contrast, color or clearness and inview of shock resistance of the liquid crystal display panel.

In a liquid crystal panel device of this kind, mixture of air bubbleswhen filling the transparent resin between the cover glass and theliquid crystal display panel will result in bright points at the time ofincidence of light which remarkably degrades the picture qualities sothat it is required to perform bonding without leaving any air bubblesbetween the substrates.

A generally known method for bonding two substrates such as a liquidcrystal display panel and a cover glass using liquid transparent resinis the so-called inversion method. In the inversion method, as shown inFIG. 8, a liquid adhesive 102 is applied onto an adhesive surface of onesubstrate 100 of a pair of substrates 100, 101 to be bonded (FIG. 8A)and the substrate 100 is inversed to make the surface applied with theadhesive oppose an adhesive surface of the other substrate 101 (FIG.8B). By approximate and pressure joining the substrates 100, 101 (FIG.8C), the adhesive 102 is made to fit and spread between the substrates100, 101 (FIG. 8D).

However, since the substrate applied with the liquid adhesive isinversed in the inversion method, it might by that dipping of theadhesive might cause scattering of the adhesive at the time of inversionor the like and that the adhesive adheres to spots other than thespecified positions. Air bubbles are accordingly mixed at the time ofadhering the substrates 100, 101, and such air bubbles will remain sinceit is impossible to fit and spread the adhesive between the substrates100, 101 while eliminating the air bubbles. Moreover, the inversionmethod requires a larger-sized manufacturing facility the larger thesize of the substrates to be adhered becomes which will lead toincreased manufacturing costs.

Further, the so-called gap dispense method is a known bonding method ofdisk substrates such as DVDs. In the gap dispense method, as shown inFIG. 9, each of a pair of substrates 110, 111 to be bonded is held toface each other at a specified clearance (FIG. 9A) and a dispensingnozzle 112 is inserted between the substrates 110, 111 (FIG. 9B). Anadhesive 113 is then injected from the dispensing nozzle 112 betweenboth substrates while contacting these substrates (FIG. 9C) whereuponthe adhesive 113 is dispersed over the entire clearance between bothsubstrates by rotating both substrates 110, 111 (FIG. 9D).

According to this gap dispense method, it is possible to effectivelyprevent mixing of air bubbles at the time of bonding the substrates bysupplying the adhesive 113 while making the adhesive contact theadhesive surfaces of both substrates that are held to face each other.Moreover, the gap dispense method is capable of dispersing, afterinjection of the adhesive, the adhesive over the entire surfaces of bothsubstrates due to rotation of the substrates, of shaking off excessadhesive to the periphery, and of eliminating air bubbles.

However, when the gap dispense method is applied to bonding oflarge-sized substrates, the adhesive will not be dispersed throughrotation but the adhesive will be fit and spread over the entiresubstrates by approximate the substrates since large-sized substrateshave large adhesive areas and are of rectangular shape. Accordingly, thetime required for fitting and spreading the adhesive will become longeraccompanying the increase in size of the substrates which leads to alonger cycle time.

When a pattern for applying the adhesive by the dispensing nozzle is setto cover a wide area in order to shorten the time required for fittingand spreading, it might happen that an obstruction area is formed by theadhesive, leaving air bubbles. There are many restrictions for drawingpatterns of adhesive for preventing occurrence of such obstruction areasso that the adhesive cannot be applied over a wide area of thesubstrates which consequently makes it difficult to shorten the timerequired for fitting and spreading.

PRIOR-ART DOCUMENTS Patent Document

PTL 1: Japanese Patent Application Laid-Open No. 2003-186011

SUMMARY OF THE INVENTION

It is accordingly an object of the present invention to provide a methodof manufacturing a plate-shaped bonded body, a bonding device and aplate-shaped bonded body with which it is possible to fit and spreadadhesive in a short time for bonding the substrates without leaving airbubbles.

For solving the above-mentioned subject, the method of manufacturing aplate-shaped bonded body according to the present invention includes aholding step in which respective adhesive surfaces of a first substrateand a second substrate are made to face each other and in which theadhesive surface of the second substrate is held on the first substratewhile making the adhesive surface of the second substrate warp towardsthe first substrate side: a discharging step in which a dispensingnozzle is inserted into a most approximate position of the firstsubstrate and the second substrate and in which a liquid filler isdischarged from the dispensing nozzle to adhere to the first substrateand the second substrate; and a filling step in which pressing membersare disposed on the second substrate at a position corresponding to themost approximate position and in which the liquid filler is fit andspread between the first and second substrates by making the pressingmembers move on the second substrate, wherein the second substrate isheld in parallel to the first substrate in correspondence with movingpositions of the pressing member.

The bonding device according to the present invention comprises amounting portion on which a first substrate is mounted, a supportingportion for holding end portions of a second substrate that is made toface the first substrate and for supporting the second substrate abovethe first substrate while warping a main surface of the second substratetowards the first substrate side, a dispenser nozzle that is insertedinto a most approximate position between the first substrate mounted onthe mounting portion and the second substrate supported by thesupporting portion for discharging a liquid filler over a rangeextending between the first substrate and the second substrate, andpressing members that are disposed on the second substrate at a positioncorresponding to the most approximate position for fitting and spreadingthe liquid filler between the first and second substrates by moving onthe second substrate, wherein the second substrate is held in parallelto the first substrate in correspondence with moving positions of thepressing members.

The plate-shaped bonded body according to the present invention ismanufactured by using the above method of manufacturing a plate-shapedbonded body.

Effects of Invention

According to the present invention, by injecting a liquid filler at amost approximate position between a first substrate and a secondsubstrate, the liquid filler is made to adhere on both of the surfacesof the first substrate and second surface and the liquid filler is fitand spread from this position by means of laminating rollers. Accordingto this invention, since end portions of the second substrate are heldin parallel to the first substrate in accordance with rolling movementsof the laminating rollers at this time, no air bubbles will mix into theliquid filler and since the liquid filler is fit and spread inaccordance with rolling movements of the laminating rollers, it ispossible to perform filling over the entire surfaces in a short timeeven if the first substrate and the second substrate are of large sizes.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1: FIG. 1 is a sectional view showing a plate-shaped bonded body inwhich a polarizing plate and a cover glass are bonded by means of atransparent resin.

FIG. 2: FIG. 2 is a side view showing a bonding device for aplate-shaped bonded body from one side.

FIG. 3: FIG. 3 is a side view showing the bonding device for aplate-shaped bonded body from the other side.

FIG. 4: FIG. 4 is a view showing a dispenser nozzle, wherein FIG. 4A isa sectional view, FIG. 4B is a plan view, and FIG. 4C is a side view.

FIG. 5: FIG. 5 is a sectional view showing the dispenser nozzle duringdischarge of a transparent resin.

FIG. 6: FIG. 6 is a side view showing manufacturing steps of aplate-shaped bonded body, wherein FIG. 6A shows a step of drawing atransparent resin pattern on an adhesive surface of the polarizing plateat which it is adhered to the cover glass, FIG. 6B shows a step ofholding the cover glass such that a specified clearance is formedbetween its curve top portion and the polarizing plate, FIG. 6C shows astep of drawing a proximate pattern at which the transparent resinadheres over both of the surfaces of the polarizing plate and the coverglass, FIG. 6D shows a step of descending a first roller on a mostapproximate position of the cover glass, FIG. 6E shows a step ofdescending a second roller on the most approximate position of the coverglass, FIG. 6F shows a step of rolling the first and second rollers andfilling the transparent resin over the entire range between thepolarizing plate and the cover glass, and FIG. 6G shows a condition inwhich filling of the transparent resin over the entire range between thepolarizing plate and the cover glass is completed.

FIG. 7: FIG. 7 is a perspective view showing manufacturing steps of aplate-shaped bonded body, wherein FIG. 7A shows a step of drawing atransparent resin pattern on an adhesive surface of the polarizing plateat which it is adhered to the cover glass, FIG. 7B shows a step ofholding the cover glass such that a specified clearance is formedbetween its curve top portion and the polarizing plate, FIG. 7C show s astep of drawing a proximate pattern at which the transparent resinadheres over both of the surfaces of the polarizing plate and the coverglass, FIG. 7D shows a step of descending a first roller on a mostapproximate position of the cover glass, FIG. 7E shows a step ofdescending a second roller on the most approximate position of the coverglass, FIG. 7F shows a step of rolling the first and second rollers andfilling the transparent resin over the entire range between thepolarizing plate and the cover glass, and FIG. 7G shows a condition inwhich filling of the transparent resin over the entire range between thepolarizing plate and the cover glass is completed.

FIG. 8: FIG. 8A to FIG. 8D are side views showing steps of bondingsubstrates according to an inversion method.

FIG. 9: FIG. 9A to FIG. 9D are side views showing steps of bondingsubstrates according to a gap dispense method.

DETAILED DESCRIPTION OF THE INVENTION

The method of manufacturing a plate-shaped bonded body, the bondingdevice and the plate-shaped bonded body to which the present inventionis applied will now be explained in details while referring to thedrawings. The present bonding device 1 for a plate-shaped body is usedfor manufacturing a liquid crystal display panel for use as alarge-sized TV monitor or the like in which a cover glass is bonded ontoa display surface using transparent resin.

<Plate-Shaped Bonded Body 2>

A plate-shaped bonded body 2 is suitable for use as a large-sized TVmonitors having a size larger than, for instance, 32 inches, but it isalso applicable for smaller sizes. In the present embodiment,explanations will be made as one example about a plate-shaped bondedbody 2 as shown in FIG. 1 in which a cover glass 6 made of a temperedglass plate having a diagonal dimension of 40 inches and a thickness of0.7 mm is bonded onto a polarizing plate 5 having a diagonal dimensionof 40 inches that is provided on a display surface of a liquid crystaldisplay panel 4 comprised of a liquid crystal layer and oriented filmand others by using a transparent resin 7 having a refractive indexequivalent to that of the cover glass 6.

The transparent resin 7 is, for instance, a transparent ultravioletcuring type elastic resin with a refractive index that is controlled torestrict scattering of light such that the visibility of the liquidcrystal panel 2 is not harmed even when the resin is filled between thepolarizing plate 5 and the cover glass 6.

The viscosity of the transparent resin 7 is selected to be in a rangeof, for example, 700 mPa·s to 5000 mPa·s which is a viscosity with whichthe resin can be filled while adhering simultaneously to the polarizingplate 5 and the cover glass 6 and with which a condition in which theresin adheres to the polarizing plate 5 and the cover glass 6 held at aspecified clearance can be maintained. In accordance with such aviscosity of the transparent resin 7, a clearance dimension of thepolarizing plate 5 and the cover glass 6 is set to be in a range of 3.5mm to 10 mm. More particularly, in the present embodiment, a transparentelastic resin of ultraviolet curing type having a viscosity of 3500mPa·s is used as the transparent resin 7 and, as it will be describedlater, the clearance of a position at which the polarizing plate 5 andthe cover glass 6 are most approximate is maintained to be 5.5 mmwhereupon the transparent resin 7 is injected to this position.

According to this plate-shaped bonded body 2, by bonding the polarizingplate 5 and the cover glass 6 by means of the transparent resin 7, it ispossible to achieve improvements in picture qualities such as contrast,color and clearness and to improve the shock resistance of the liquidcrystal display panel.

<Bonding Device 1>

A bonding device 1 for bonding the polarizing plate 5 and the coverglass 6 by means of the transparent resin 7 comprises, as shown in FIG.2 and FIG. 3, a mounting portion 10 on which the polarizing plate 5 ismounted, a cover glass supporting portion 11 for supporting the coverglass 6 while making the cover glass face the polarizing plate 5 that issupported by the mounting portion 10, a dispensing nozzle 12 forinjecting the transparent resin 7 between the polarizing plate 5 and thecover glass 6 that are held to face each other by means of the mountingportion 10 and the cover glass supporting portion 11, and laminatingrollers 13 that are rolled on the cover glass 6 to make the transparentresin 7 fit and spread between the polarizing plate 5 and the coverglass 6.

The bonding device 1 further comprises a nozzle moving mechanism 15 formoving the dispensing nozzle 12, a pressing mechanism 16 for making thetransparent resin 7 be discharged from a discharge outlet 22 of thedispensing nozzle 12, an elevating mechanism 17 for elevating the coverglass supporting portion 11, a roller driving mechanism 18 for drivingthe laminating rollers 13, and a control portion 20 for controllingthese mechanisms 15 to 18, all of which are arranged on a table 19.

<Mounting Portion/Supporting Portion>

The mounting portion 10 on which the polarizing plate 5 is mounted isfixed on the table 19 and the polarizing plate 5 is held to facevertically upward such that its adhesive surface faces the cover glass 6by means of vacuum holding or the like.

The cover glass supporting portion 11 for supporting the cover glass 6holds the cover glass 6 such that its adhesive surface at which itadheres to the polarizing plate 5 faces upward by engaging outerperipheral edges of the cover glass 6 or by means of a holding meanssuch as vacuum holding or the like. With this arrangement, a centralportion of the cover glass 6 in the longitudinal direction is warpedtowards the polarization plate 5 over a width direction so that a curvetop portion of the cover glass 6 becomes a most approximate position Awith the polarizing plate 5.

The most approximate position A has a clearance at which the transparentresin 7 having a specified viscosity adheres to the polarizing plate 5and the curve top portion of the cover glass 6 at the most approximateposition A upon inserting the dispensing nozzle 12 (to be describedlater) and injecting the transparent resin 7. For instance, when theviscosity of the transparent resin 7 is 3500 mPa·s, the clearance at themost approximate position A is set to be 5.5 mm. Further, at the mostapproximate position A, the laminating rollers 13 descend and roll in alongitudinal direction of the cover glass 6 such that transparent resin7 is dispersed while adhering to the polarizing plate 5 and the coverglass 6.

The cover glass supporting portion 11 is supported above the mountingportion 10 to be elevating by means of the elevating mechanism 17. Theelevating mechanism 17 is comprised of a power means such as an actuatorand elevates the cover glass supporting mechanism 11 in verticaldirections which is a direction in the arrow Z or a direction againstthe arrow Z in FIG. 2.

The elevating mechanism 17 elevates the cover glass supporting portion11 when the polarizing plate 5 or the cover glass 6 is supported by themounting portion 10 or the cover glass supporting portion 11. Wheninjecting the transparent resin 7 between the polarizing plate 5 and thecover glass 6 for bonding, the elevating mechanism 17 descends the coverglass supporting portion 11 so that the cover glass 6 approximates thepolarizing plate 5 and holds the polarizing plate 5 and the cover glass6 at a specified clearance through which the dispensing nozzle 12 can beinserted and the transparent resin 7 can be applied while contacting thepolarizing plate 5 and the cover glass 6. After filling the transparentresin 7, the elevating mechanism 17 further descends the cover glasssupporting portion 11 in accordance with the rolling of the laminatingrollers 13 (to be described later) and holds the cover glass 6 inparallel to the polarizing plate 5 so as to expand the transparent resin7 over the entire surfaces of the polarizing plate 5 and the cover glass6 without mixing air bubbles therein.

<Dispensing Nozzle/Nozzle Moving Mechanism>

The dispensing nozzle 12 for discharging the transparent resin 7 betweenthe polarizing plate 5 and the cover glass 6 has a cylindrical body thatis supported in parallel to a main surface of the polarizing plate 5held by the mounting portion 10. The dispensing nozzle 12 is furtherconnected to a pressurizing means 21 such as a syringe or tank forsupplying the transparent resin 7. The dispensing nozzle 12 is supportedby the nozzle moving mechanism 15 at a height at which it is movableback and forth through the clearance between both substrates along themost approximate position A of the polarizing plate 5 and the coverglass 6 without contacting both substrates. The dispensing nozzle 12moves in a direction against the arrow X in FIG. 3, in a direction ofarrow Z in FIG. 2 and in a direction that is orthogonal to the sheet fordrawing a specified discharge pattern by the transparent resin 7 alongthe most approximate portion A within the clearance between thepolarizing plate 5 and the cover glass 6.

As shown in FIG. 4, the dispensing nozzle 12 is comprised of a nozzlemain body 12 a made of metal or industrial plastic and a soft resinlayer 12 b for coating the nozzle main body 12 a so as not to damage thepolarizing plate 5 and the cover glass 6. The resin layer 12 b is formedby, for instance, baking finishing resin exhibiting superior lowfrictional, wear-resistant, water-repellent and corrosion-resistantcharacteristics such as fluorine resin onto the surface of the nozzlemain body 12 a. It should be noted that the dispensing nozzle 12 is notlimited to one having a circular sectional shape and it might also havea flat circular or rectangular shape.

There is no fear that the dispensing nozzle 12 damages the polarizingplate 5 and the cover glass 6 even if the nozzle comes into slidingcontact with the polarizing plate 5 and the cover glass 6 due to theformation of the resin layer 12 b when the nozzle discharges thetransparent resin 7 while moving through the clearance between thepolarizing plate 5 and the cover glass 6. More particularly, thedischarge nozzle is formed of metal or industrial plastic and appliesthe transparent resin 7 while moving through the clearance between thepolarizing plate 5 and the cover glass 6 along the most approximateposition A by means of the nozzle moving mechanism 15. At this time, thedispensing nozzle 12 is moved so as not to abut the polarizing plate 5and the cover glass 6; however, even if the nozzle abuts the polarizingplate 5 and the cover glass 6 due to oscillation or warping, there is nofear that the polarizing plate 5 and the cover glass 6 are damaged sincethe nozzle is coated by the resin layer 12 b.

Further, the provision of the resin layer 12 b that exhibits superiorwater-repelling and corrosion-resistant properties for the dispensingnozzle 12 also prevents so-called dripping in which the transparentresin 7 drips from the discharge outlet 22 even after termination ofdischarge. The dispensing nozzle 12 is accordingly capable of applyingtransparent resin 7 to only specified portions while preventingconditions in which the transparent resin 7 is adhered to unexpectedportions.

Moreover, since the dispensing nozzle 12 can prevent damages causedthrough contact with the polarizing plate 5 and the cover glass 6, it ispossible to apply the transparent resin 7 without reducing the movingspeed by the nozzle moving mechanism 15, Accordingly, the time duringwhich the transparent resin 7 discharged at an earlier time and thetransparent resin 7 discharged at a later time is exposed to air willnot differ largely and no differences in filling characteristics orcuring characteristics will be caused. While it is desirable to finishapplication of the transparent resin 7 quickly without reducing thenozzle moving speed while the time required for the application step ofthe transparent resin 7 increases the larger the substrate becomes, thebonding device 1 is advantageously capable of applying the transparentresin 7 without reducing the moving speed of the nozzle moving mechanism15.

The dispensing nozzle 12 might also be arranged as shown in FIG. 4A andFIG. 4C in that the discharge outlet 22 faces vertically upward bycutting an upper surface of its tip end to be oblique. With thisarrangement, upon start of discharge of the transparent resin 7, thedispensing nozzle 12 first adheres the transparent resin 7 onto thecover glass 6 that is located upward and then to the lower polarizingplate 5 through gravity. The dispensing nozzle 12 then moves through theclearance between the polarizing plate 5 and the cover glass 6 whiledischarging the transparent resin 7 and applies the resin in a conditionin which the transparent resin 7 is constantly adhering to both of thesurfaces of the polarizing plate 5 and the cover glass 6 as shown inFIG. 5.

In this manner, the bonding device 1 directs the discharge outlet 22 ofthe dispensing nozzle 12 upward while it applies the transparent resin 7such that it continuously adheres to both of the surfaces of thepolarizing plate 5 and the cover glass 6 so as to prevent air bubblesfrom remaining in the transparent resin 7.

<Approximate Position/Curve Top Portion>

Such a dispensing nozzle 12 is inserted by the nozzle moving mechanism15 into a range between the curve top portion of the cover glass 6 thatis held by the cover glass supporting portion 11 and the polarizingplate 5. This position is the most approximate position A at which thepolarizing plate 5 and the cover glass 6 are most approximate, and thetransparent resin 7 is injected into this position A.

When the dispensing nozzle 12 is inserted into the most approximateposition A of the polarizing plate 5 and the cover glass 6 from the sideas shown in FIG. 7C, the nozzle discharges the transparent resin 7 whilemoving back from one end side in the width direction towards theinserting end side (direction against arrow X). With this arrangement,the dispensing nozzle 12 can discharge the transparent resin 7 whileadhering the resin to both of the surfaces of the polarizing plate 5 andthe cover glass 6 at the most approximate position A.

In this respect, the nozzle moving mechanism 15 moves the dispensingnozzle 12 and the pressurizing means 21 in parallel to the polarizingplate 5 mounted on the mounting portion 10 upon receiving controlsignals from the control portion 20 and is comprised with, for instance,a mutually crossing rail mechanism. The nozzle moving mechanism 15 holdsthe dispensing nozzle 12 in a width direction of the polarizing plate 5as shown by arrow X in FIG. 3 and is freely movable back and forth inthe direction of arrow X and against the direction of arrow X. Thenozzle moving mechanism is also movable in a longitudinal direction ofthe polarizing plate 5 (a direction orthogonal to the direction of arrowX in FIG. 3 and a direction parallel to the polarizing plate 5) and itis also capable of positioning the dispensing nozzle 12 at the mostapproximate position A.

The pressurizing means 21 for supplying the transparent resin 7 storestherein the adhesive 7 that is discharged from the dispensing nozzle 12.The pressurizing means 21 is further connected to a pressing mechanism16 for making the stored transparent resin 7 be discharged by thedispensing nozzle 12, and control of discharge and discharge terminationof the transparent resin 7 and control of discharge pressure isperformed. As for the pressing mechanism 16, it is, for instance,possible to use a compression dry air cylinder wherein control of supplyand termination of supply of gas into the pressurizing means 21 as wellas of supply pressure is performed by the control portion 20, and bysupplying gas into the pressurizing means 21 at a specified pressure,the transparent resin 7 is discharged from the dispensing nozzle 12.

<Laminating Rollers>

The laminating rollers 13 are for fitting and spreading the transparentresin 7 between the polarizing plate 5 and the cover glass 6 into whichthe transparent resin 7 has been injected through the dispensing nozzle12. The laminating rollers 13 have a columnar shape and are arranged tobe elevating above the cover glass 6 and to be rolling in a longitudinaldirection of the cover glass 6 by being supported by the roller drivingmechanism 18.

The laminating rollers 13 are supported by the roller driving mechanism18 such that their longitudinal direction is parallel to the mostapproximate position A of the polarizing plate 5 and the cover glass 6while they are descended to the most approximate position A and arerolled from the most approximate position A in the longitudinaldirection of the polarizing plate 5 and the cover glass 6. With thisarrangement, the laminating rollers 13 fit and spread the transparentresin 7 over the rolling direction so as to fill the resin over theentire range between the polarizing plate 5 and the cover glass 6.

The laminating rollers 13 are comprised of a first roller 13 a thatrolls from the most approximate position A of the polarizing plate 5 andthe cover glass 6 towards one side in the longitudinal direction and asecond roller 13 b that rolls from the most approximate position A ofthe polarizing plate 5 and the cover glass 6 towards the other side inthe longitudinal direction. The roller driving mechanism 18 descends thefirst roller 13 a to the most approximate position A to make the rollerroll towards one side in the longitudinal direction and descends thesecond roller 13 b to the most approximate position A to make the rollerroll towards the other side in the longitudinal direction. With thisarrangement, the first and second rollers 13 a, 13 b can fill thetransparent resin 7 over the entire range between the polarizing plate 5and the cover glass 6.

In accordance with the rolling of the laminating rollers 13 by theroller driving mechanism 18, the above-described elevating mechanism 17descends the cover glass supporting portion 11 and descends the outerperipheral edge portions of the cover glass 6 to the polarizing plate 5side. With this arrangement, the cover glass 6 that had been supportedin a warped manner is gradually flattened towards the one or the otherend in the longitudinal direction from the most approximate position Ato become parallel to the polarizing plate 5 so that it does not receivethe load caused through the rolling of the laminating rollers 13.Further, since the cover glass 6 is supported to keep a specifiedclearance with respect to the polarizing plate 5 in accordance with therolling of the laminating rollers 13, it is possible to exhaust air inthe clearance with the polarizing plate 5 to the exterior throughadhesion of the fitting and spreading transparent resin 7 and no airbubbles will remain in the clearance with the polarizing plate 5.

<Manufacturing Step of the Plate-Shaped Bonded Body 2>

Next, steps of manufacturing a plate-shaped bonded body 2 in which thepolarizing plate 5 and the cover glass 6 are bonded using such a bondingdevice 1 will be explained while referring to FIG. 6 and FIG. 7. In thepresent embodiment, explanations will be made as one example aboutmanufacturing the above-described plate-shaped bonded body 2 in which acover glass 6 made of a tempered glass plate having a diagonal dimensionof 50 inches and a thickness of 0.7 mm is bonded onto a rectangularpolarizing plate 5 having a length of 900 mm, a width of 500 mm and adiagonal dimension of 40 inches that is provided on a display surface ofa liquid crystal display panel using a transparent resin 7 having arefractive index equivalent to that of the cover glass 6.

First, the polarizing plate 5 is mounted onto the mounting portion 10.At this time, the polarizing plate 5 is held by means of vacuum holdingor the like after positioning on the mounting portion 10, and itsadhesive surface at which it is adhered to the cover glass 6 is made toface vertically upward.

Then, as shown in FIG. 6A and FIG. 7A, a pattern P is drawn onto thepolarizing plate 5 onto its adhesive surface at which it is adhered tothe cover glass 6 by applying the transparent resin 7 thereon. While itis preferable that the transparent resin 7 is the same resin as thetransparent resin 7 that is injected by the dispensing nozzle 12 in alater step, it might also be a transparent adhesive having the samerefractive index as that of the transparent resin 7, an equivalentviscosity (3500 mPa·s) and hardly different physical properties. In theapplication step of the transparent resin 7, a pattern is drawn by therolling of the laminating rollers 13 in which the transparent resin 7 isfit and spread over the entire surfaces of the polarizing plate 5 andthe cover glass 6 without mixing air bubbles therein. For instance, inthe present embodiment, a pattern P that is comprised of a plurality oflines extending in longitudinal directions at specified intervals in thewidth direction of the polarizing plate 5 is drawn as shown in FIG. 7A.The amount of application of the transparent resin 7 is adjusted withregards to the thickness of the resin layer after curing. For instance,in the pattern P, there are drawn 13 lines at intervals betweenrespective line centers being 33 mm and such that the amount ofapplication of the transparent resin 7 is 14 g, and the thickness of theresin layer after curing becomes 400 μm. In this respect, the drawingstep of the pattern P might also be performed using the dispensingnozzle 12 and it is also possible to employ other means.

The cover glass 6 is supported by the cover glass supporting portion 11.At this time, the cover glass supporting portion 11 is elevated by theelevating mechanism 17 to be above the mounting portion 10. The coverglass supporting portion 11 holds the outer peripheral edges on bothsides of the cover glass 6 in the longitudinal direction by about 20 mmby means of suction from above or other means. With this arrangement,the cover glass 6 is made to warp by its own weight at its centralportion in the longitudinal direction over its width direction towardsthe polarizing plate 5 side. At this time, a height of an end portion ofthe cover glass 6 to its curve top portion will be approximately 100 mmas shown in FIG. 2.

While maintaining this condition, the elevating mechanism 17 descendsthe cover glass supporting portion 11 as shown in FIG. 6B and FIG. 7B tohold the cover glass 6 at a height at which the clearance between thecurve top portion and the polarizing plate 5 becomes a specifieddistance (5.5 mm). Then, this position at which the curve top portion ofthe cover glass 6 and the polarizing plate face each other will be themost approximate position A at which the dispensing nozzle 12 isinserted and at which the laminating rollers 13 descend.

Next, the nozzle moving mechanism 15 inserts the dispensing nozzle 12into the most approximate position A from the side of the polarizingplate 5 and the cover glass 6 and while moving the nozzle back from theone end side in the width direction to the inserting end side (againstdirection of arrow X), the pressing mechanism 16 makes the transparentresin 7 within the pressurizing means 21 be discharged through thedispensing nozzle 12. As shown in FIG. 6C and FIG. 7C, the dispensingnozzle 12 draws an approximate pattern N at which the transparent resin7 adheres over both of the surfaces of the polarizing plate 5 and thecover glass 6 with the nozzle discharging the transparent resin 7 whilemoving back against the direction of arrow X in FIG. 5 and FIG. 7C alongthe most approximate position A at which the curve top portion of thecover glass 6 and the polarizing plate 5 are held at a specifiedclearance. Since the approximate pattern N is drawn along the mostapproximate position A over the width direction of the polarizing plate5 and the cover glass 6 so that it crosses the pattern P that has beenpreliminarily drawn onto the polarizing plate 5. In this respect, theamount of application of the transparent resin 7 for the approximatepattern N is set to be, for instance, 15 g.

Upon completion of injection of the transparent resin 7 at the mostapproximate position A, the nozzle moving mechanism 15 moves thedispensing nozzle 12 back from between the polarizing plate 5 and thecover glass 6. Next, the elevating mechanism 17 descends the cover glasssupporting portion 11, approximates the cover glass 6 to the polarizingplate 5 and presses the transparent resin 7 whereas the roller drivingmechanism 18 descends the laminating rollers 13 to be on the mostapproximate position A of the cover glass 6.

The roller driving mechanism 18 first descends, as shown in FIG. 6D andFIG. 7D, the first roller 13 a to be on the most approximate position Aof the cover glass 6 and makes it roll towards the one end side in thelongitudinal direction of the cover glass 6. With this arrangement, thetransparent resin 7 that had been preliminarily applied on thepolarizing plate 5 in form of lines and the transparent resin 7 that hasbeen injected by the dispensing nozzle 12 along the most approximateposition A will become uniform in accordance with the rolling of thefirst roller 13 a towards the one end side in the longitudinal directionbetween the polarizing plate 5 and the cover glass 6 to be fit andspread.

At this time, the elevating mechanism 17 operates the cover glasssupporting portion 11 in accordance with the rolling of the first roller13 a such that the one end side of the cover glass 6 in the longitudinaldirection descends. Accordingly, the cover glass 6 will become flat atits one end side in the longitudinal direction to be parallel to thepolarizing plate 5 such that no load is applied by the first roller 13a.

More particularly, since the transparent resin 7 that is inserted intothe most approximate position A and adhered to both of the surfaces ofthe polarizing plate 5 and the cover glass 6 fits and spreads uniformlywith the transparent resin 7 that had been preliminarily applied on thepolarizing plate 5 accompanying the rolling of the first roller 13 a andsince the cover glass 6 is made to be parallel to the polarizing plate 5in accordance with the first roller 13 a, the transparent resin 7 is fitand spread without air mixing into the clearance with the cover glassand the polarizing plate 5.

Moreover, since the transparent resin 7 is applied in form of lines atspecified intervals in the longitudinal direction of the polarizingplate 5 and the cover glass 6, an escape path of air is secured alongthe rolling direction of the first roller 13 a and since the transparentresin 7 is fit and spread accompanying the rolling of the first roller13 a, air will not be surrounded by the transparent resin 7 butexhausted from between the polarizing plate 5 and the cover glass 6.

Further, since the transparent resin 7 is fit and spread accompanyingthe rolling of the first roller 13 a, the resin is filled at a uniformthickness over the entire surfaces between the polarizing plate 5 andthe cover glass 6. More particularly, the first roller 13 a is made toroll at a constant height on the cover glass 6 by means of the rollerdriving mechanism 18 while the cover glass 6 is made to be parallel tothe polarizing plate 5 by means of the elevating mechanism 17 so thatthe thickness between the polarizing plate 5 and the cover glass 6 canbe made uniform over the entire surfaces.

As shown in FIG. 6E and FIG. 7E, following the rolling of the firstroller 13 a, the roller driving mechanism 18 descends the second roller13 b to be on the most approximate position A of the cover glass 6 forrolling the roller towards the other end side in the longitudinaldirection of the cover glass 6. With this arrangement, the transparentresin 7 that had been preliminarily applied onto the polarizing plate 5in form of lines and the transparent resin 7 that is injected into themost approximate position A by the dispensing nozzle 12 are fit andspread between the polarizing plate 5 and the cover glass 6 towards theother end side in the longitudinal direction in accordance with therolling of the second roller 13 b.

At this time, the elevating mechanism 17 operates, similarly to the casewith the first roller 13 a, the cover glass supporting portion 11 suchthat the other end side in the longitudinal direction of the cover glass6 descends in accordance with the rolling of the second roller 13 b.With this arrangement, the transparent resin 7 is fit and spread at auniform thickness without air mixing to the other end side in thelongitudinal direction of the cover glass 6 accompanying the rolling ofthe second roller 13 b.

As shown in FIG. 6F and FIG. 7F, descending and rolling of the first andsecond rollers 13 a, 13 b is continuously performed, and as shown inFIG. 6G and FIG. 7G, filling of the transparent resin 7 over the entirerange between the polarizing plate 5 and the cover glass 6 is completedalmost simultaneously. Thereafter, ultraviolet rays are irradiated ontothe transparent resin 7 filled between the polarizing plate 5 and thecover glass 6 for curing and accordingly manufacturing the plate-shapedbonded body 2.

According to such a method of manufacturing a plate-shaped bonded body2, the transparent resin 7 is adhered to both of the surfaces of thepolarizing plate 5 and the cover glass 6 by injecting the transparentresin 7 into the most approximate position A of the polarizing plate 5and the cover glass 6, and the transparent resin 7 is fit and spreadfrom this position by means of the laminating rollers 13. At this time,according to the present method of manufacturing, since an end portionof the cover glass 6 is descended to the polarizing plate 5 side inaccordance with the rolling of the laminating rollers 13, no air bubbleswill be mixed into the transparent resin 7 and since the transparentresin 7 is fit and spread in accordance with the rolling of thelaminating rollers 13, it is possible to perform filling over the entiresurfaces in a short time even if the size of the polarizing plate 5 andthe cover glass 6 is increased.

<Other Structures>

In this respect, while the cover glass 6 has been set such that bothends thereof are held by the cover glass supporting portion 11 in aneven manner while its central portion becomes lowest in the abovemanufacturing step, it is also possible that injection of thetransparent resin 7 by the dispensing nozzle 12 and descending of thelaminating rollers 13 is performed by providing a curve top portion in aregion other than the central portion by differing heights for holdingboth ends of the cover glass 6 and setting a clearance between the curvetop portion and the polarizing plate 5 as the most proximate position A.

In the above manufacturing step, while the pattern P is preliminarilydrawn onto the polarizing plate 5 and the approximate pattern N is drawnat the most approximate position A by the dispensing nozzle 12 afterdescending the cover glass 6, it is also possible to draw the pattern Pand the approximate pattern N by the dispensing nozzle 12 afterdescending the cover glass 6 without preliminarily drawing the pattern Ponto the polarizing plate 5.

In the above manufacturing step, while both ends of the cover glass 6are held by the cover glass supporting portion 11 to bend the coverglass towards the polarizing plate 5 side through warping by its ownweight, it is possible to further warp the cover glass when compared towarpage by its own weight or to decrease the amount of warpage whencompared to warpage by its own weight by taking measures other thanbending through its own weight such as adjusting the holding clearanceof both ends of the cover glass 6 through the cover glass supportingportion 11 provided that the clearance between the curve top portion andthe polarizing plate 5 can be adjusted.

In the above manufacturing step, while ultraviolet rays are irradiatedafter filling the transparent resin 7 over the entire surfaces of thepolarizing plate 5 and the cover glass 6, it is also possible toirradiate ultraviolet rays during rolling of the laminating rollers 13provided that the transparent resin is filled over the entire surfacesof the polarizing plate 5 and the cover glass 6 without mixing airbubbles therein and the thickness is controlled to be uniform.

In the present invention, while the first roller 13 a and the secondroller 13 b are used as the laminating rollers 13 that are mutuallyrolled in opposite directions from the most approximate position A,other arrangements are also possible in which, for instance, onelaminating rollers is rotated from the most approximate position Atowards one end side of the cover glass 6 whereupon the rollingdirection is inversed so as to roll the roller towards the other endside of the cover glass 6 for fitting and spreading the transparentresin 7 over the entire surfaces of the polarizing plate 5 and the coverglass 6.

In the present invention, it is also possible to employ three or morelaminating rollers 13 in accordance with the shape or size of theplate-shaped bonded body 2. In the present invention, it is possible todrive the laminating rollers 13 to reciprocate between the mostapproximate position A and the one end or the other end of the coverglass 6 if required. Moreover, in the present invention, it is possibleto make a plurality of rollers roll from the most approximate position Ato the one end or other end of the cover glass 6.

In the present invention, it is further possible to make a pressingmeans other than the rollers wing or move from the most approximateposition A to the one end or the other end on the cover glass 6 as longas the liquid filler can be fit and spread between a pair of substratesthat constitute the plate-shaped bonded body 2 in a short time withoutmixing air bubbles therein.

REFERENCE SIGNS LIST

1 . . . bonding device, 2 . . . plate-shaped bonded body, 5 . . .polarizing plate, 6 . . . cover glass, 7 . . . transparent resin, 10 . .. mounting portion, 11 . . . cover glass supporting portion, 12 . . .dispensing nozzle, 13 . . . laminating rollers, 13 a . . . first roller,13 b . . . second roller, 15 . . . nozzle moving mechanism, 16 . . .pressing mechanism, 17 . . . elevating mechanism, 18 . . . rollerdriving mechanism, 20 . . . control portion, 21 . . . pressurizingmeans, 22 . . . discharge outlet

1. A plate-shaped bonded body manufactured by a method including: aholding step in which respective adhesive surfaces of a first substrateand a second substrate are made to face each other and in which theadhesive surface of the second substrate is held above the firstsubstrate while making the adhesive surface of the second substrate warptowards the first substrate side: a discharging step in which adispensing nozzle is inserted into a most approximate position of thefirst substrate and the second substrate and in which a liquid filler isdischarged from the dispensing nozzle while adhering to the firstsubstrate and the second substrate; and a filling step in which pressingmembers are disposed on the second substrate at a position correspondingto the most approximate position and in which the liquid filler is fitand spread between the first and second substrates by making thepressing members move on the second substrate, wherein the secondsubstrate is held in parallel to the first substrate in accordance withmoving positions of the pressing members.